1. Field of the Invention
The present invention relates to a backlight module, and in particular to a backlight module reducing the thickness and weight of an LCD device.
2. Description of the Related Art
Referring to FIG. 1, a conventional backlight module 1 for an LCD device includes a glass panel 2, a light guide plate 4 and two symmetric illumination assemblies 6. A diffusing film (not shown) and a brightness enhancement film (not shown) are disposed on the glass panel 2. A reflecting film (not shown) is disposed under the light guide plate 4. The illumination assembly 6 has two lamps 6a, 6b arranged in a line and a reflector 6c. The lamps 6a, 6b transmit light to the light guide plate 4 directly. Also, the lamps 6a, 6b transmit light to the light guide plate 4 by reflection of the reflector 6c and the light is absorbed and diffused by a plurality of optical dots (not shown) formed on the bottom of the light guide plate 4.
Generally speaking, the diameter of the lamps 6a, 6b is 2.4 mm. The lamps 6a, 6b are spaced from each other by a predetermined distance such that light or light energy is not absorbed and illumination of the light guide plate 4 is not reduced. In addition, a predetermined distance exists between the lamp 6a and the reflector 6c and between the lamp 6b and the reflector 6c to ensure reflection. Thus, the thickness t1 of the light guide plate 4 of the conventional backlight module 1 is 8 mm.
Referring to FIG. 2, another conventional backlight module 10 provides a light guide plate having reduced thickness. Elements corresponding to those shown in FIG. 1 are given the same reference numerals, and explanation thereof will be omitted for simplification of the description. The backlight module 10 includes a glass panel 2, a light guide plate 4 and two symmetric illumination assemblies 6xe2x80x2. The illumination assembly 6xe2x80x2 has two lamps 6a, 6b arranged obliquely and a reflector 6xe2x80x2c. Similarly, the diameter of the lamps 6a, 6b is 2.4 mm and the illumination of the light guide plate 4 in the backlight module 10 is the same as that in the backlight module 1. The thickness of the reflector 6xe2x80x2c can thus be reduced. Namely, the thickness t2 of the light guide plate 4 of the backlight module 10 is reduced to 6 mm.
Nevertheless, the aforementioned backlight modules 1, 10 are still overly thick (8 mm, 6 mm) though they maintain enough illumination.
Consequently, the invention provides a backlight module for an LCD device. The backlight module provides an improved structure of the illumination assembly and improved arrangement of the illumination lamps thereof. The illumination of the LCD device is not adversely affected and the weight and thickness of the backlight module are reduced, as are the weight and thickness of the LCD device itself.
An object of the invention is to provide a backlight module. The backlight module comprises a glass panel, a light guide plate and an illumination assembly. The light guide plate is disposed under the glass panel and has a connection side. The illumination assembly is disposed on the connection side of the light guide plate and has a reflector, a first lamp and a second lamp. The first lamp and the second lamp are enclosed by the reflector. The perpendicular distance from the first lamp to the connection side of the light guide plate is greater than that from the second lamp to the connection side of the light guide plate. The reflector is composed of a plurality of curved surfaces to reflect light from the first lamp and the second lamp to the light guide plate. Thus, the light guide plate and the illumination assembly feature reduced thickness.
Preferably, the reflector is composed of an oval surface, a first curved surface, a second curved surface, a third curved surface and a plane surface.
Preferably, the oval surface and the plane surface are connected to the connection side of the light guide plate.
Preferably, the first lamp is disposed within the first curved surface.
Preferably, the second lamp is disposed within the third curved surface.
Preferably, the first curved surface, the second curved surface and the third curved surface are further composed of a plurality of minor curved surfaces, respectively.
Preferably, a plurality of optical dots are formed on the bottom of the light guide plate for absorbing and diffusing the light input to the light guide plate.
Preferably, the reflector is made of stainless steel.
Preferably, the backlight module further comprises an optical film disposed under the light guide plate.
Preferably, the backlight module further comprises a diffusing film disposed on the glass panel.
Preferably, the backlight module further comprises a brightness enhancement film disposed on the diffusing film.
Preferably, the light guide plate is made of acrylic material.
A detailed description will be given by the following embodiments with reference to the accompanying drawings.